diff --git a/Gemfile.lock b/Gemfile.lock
index bed91370..23a81362 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -196,6 +196,7 @@ GEM
 
 PLATFORMS
   x86_64-darwin-23
+  x86_64-linux
 
 DEPENDENCIES
   addressable (~> 2.8.0)
diff --git a/lib/ncbo_annotator.rb b/lib/ncbo_annotator.rb
index 64a84105..d7b4fa79 100644
--- a/lib/ncbo_annotator.rb
+++ b/lib/ncbo_annotator.rb
@@ -733,11 +733,13 @@ def redis_last_mgrep_restart_default_timestamp()
       def create_term_entry(redis, instance_prefix, ontResourceId, resourceId, label_type, val, semanticTypes)
         begin
           # NCBO-696 - Remove case-sensitive variations on terms in annotator dictionary
-          val.upcase!()
+          val = val.dup.upcase
         rescue ArgumentError => e
+          binding.pry
+          val = val.dup
           # NCBO-832 - SCTSPA Annotator Cache building error (UTF-8)
           val = val.encode('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '')
-          val.upcase!()
+          val = val.upcase
         end
 
         # exclude single-character or empty/null values